1. Field of the Invention
This invention relates generally to an apparatus and a method for testing surgical cartridges into which discrete articles have been inserted, and more particularly for testing whether there are too many discrete articles in a surgical stapling cartridge.
2. Description of the Related Art
In the field of microsurgery, a surgical instrument having a cutting blade traverses a specific path through tissue. One feature of the surgical instrument is a single-use cartridge, shown in FIG. 1, that is a holder for surgical staples. The cartridge is an elongated plastic body with a longitudinal channel that serves as a guide for a surgical blade. The cartridge has rows of small staples on opposite sides of the channel, and these rows are aligned parallel to the guide channel. Drivers are inserted in apertures (also called “pockets”) aligned with the rows in order to push the staples out of the cartridge and through the adjacent tissue. Before the blade has made its cut, each side of the incision is stapled together by displacing the drivers relative to the cartridge. This displacement forces the staples against an anvil on the opposing side of the surgical instrument as the cartridge and the anvil deflect the points of the staples into a clasping position.
There may be as many as fifty or more very small staples on each side of a two-inch incision. Each staple can be driven into the tissue to close the incision by the correspondingly small drivers. The task of inserting the drivers into the cartridge is labor-intensive due to the small size and number of the drivers and the apertures.
It is known in the prior art to insert drivers mechanically into surgical stapling cartridges, as shown in U.S. Pat. No. 5,836,147 to Schnipke, U.S. Pat. No. 5,653,928 to Schnipke, U.S. Pat. No. 6,158,205 to Schnipke et al., and U.S. Pat. No. 7,207,168 to Doepker et al., all of which are incorporated herein by reference. Workers manually position the cartridges, as well as the holders that contain the drivers and hold them relative to the machine, in the machines disclosed in these patents, and then actuate the machine to insert the tiny drivers into the pockets in the cartridges. After a fraction of the total number of drivers is inserted by one machine, the cartridge is then manually transported to the next machine, which inserts another fraction of the drivers. In U.S. Pat. No. 6,729,119 to Schnipke et al., which is incorporated herein by reference, a robotic loader is described for use in filling the cartridges discussed herein with the use of fewer workers than the prior art.
During the surgical procedure in which the surgical cartridges described above are used, the surgeon displaces two “sleds” longitudinally by manually depressing a trigger or otherwise actuating the surgical device that holds the cartridge. During this actuation, the sleds of the cartridge drive the drivers out of their home position, thereby driving the staples into the tissue, and a knife is displaced to make the incision. It is important that the knife make the incision either after, or while, the staples are driven into the tissue.
It is possible for too many, or for fewer than the required number of, drivers to be placed in a particular aperture during assembly of the cartridge. While the latter results in harm due to a staple not being driven at one region of the incision, the former results in a jammed instrument, thereby creating a severe danger to the patient. It is extremely difficult to determine whether too many or too few drivers are placed in a particular aperture, because of the relative size of the apertures and the drivers. There is, however, no way known to Applicants to rapidly and conveniently test a cartridge to determine if it has precisely the correct number of drivers in each aperture.
Therefore, there is a need for a machine for testing whether there are too many drivers inserted in apertures in a surgical cartridge.